Psychosis, where a person suffers a clear break from reality, with hallucinations, paranoia and lack of motivation, affects two or three percent of the population. Symptoms usually appear early in adulthood and can be lifelong. Cannabidiol (CBD), one of the main ingredients of cannabis, might relieve things and make people less psychotic. If you’d like to be less psychotic, you won’t be reaching for a joint because the largest ingredient of cannabis, delta-9-tetrahydrocannabinol (THC), makes psychosis worse. THC gets you stoned, while CBD doesn’t.

What to do about psychosis?

Psychosis has been customarily treated with anti-psychotic drugs since the 1950s. These are usually at least somewhat effective; however, in about a third of folk they work not at all. They also have major side effects.

Anti-psychotic drugs function by blocking the brain’s dopamine receptors. Dopamine is a neurotransmitter, which carries signals between brain cells, that governs reward and pleasure, amongst other things. In some psychotic people, however, dopamine function is normal. So if you want people to be less psychotic, it’s worthwhile to examine other neurotransmitters to see if they’re involved.

Oh, a study!

A study by the Institute of Psychiatry, Psychology and Neuroscience of King’s College London, Cannabidiol as an Adjunctive Therapy in Schizophrenia: A Multi-Centre Randomised Controlled Trial, published in the American Journal of Psychiatry, established the link betwixt CBD and psychosis clinically. 88 people with psychosis from the United Kingdom, Poland and Romania were given 1,000 milligrams (0.035 oz) of either CBD or a placebo for six weeks, in addition to their usual drugs. Researchers and these people’s psychiatrists rated them, not knowing if they were taking CBD or the placebo. CBD made people less psychotic.

What the future holds

Although it remains unclear just how CBD works, Dr Philip McGuire, the professor of psychiatry who led the study, believes it could be “a new class of treatment” for psychotic conditions, such as schizophrenia, for which around 220,000 people are treated by the NHS each year. People with Parkinson’s disease might also benefit. Dr McGuire suggested the positive effects would be more pronounced on people who weren’t taking anti-psychotic drugs since the baseline symptoms would be higher, ie using CBD as an adjunctive therapy was not the way to go.

The usual lack-of-side-effects business

The lack of side effects is crucial, because people with psychosis often shy away from the usual drugs due to concern over side effects like dizziness, drowsiness and seizures. One large study of such people found almost every participant to be overweight, a recognised side effect of anti-psychotic drugs. Mentally ill people face almost thrice the risk of cardiovascular problems. Larger trials should follow. It’s possible that cannabis might be the future of mental illness treatment and not the cause of it.

This study wasn’t the first

A previous study conducted in Germany that was published in Translational Psychiatry in 2012 showed that CBD was better than amisulpride, a powerful anti-psychotic agent, at reducing psychosis in schizophrenic patients. This was, alas, not a placebo-controlled trial.